This invention relates to unique layered compounds formed by reacting molybdenum trioxide with a Lewis base. More particularly, Lewis bases are covalently bound to molybdenum atoms within a layered molybdenum oxide structure.
Transition metal complexes of molybdenum are well-known, e.g., [Mo(NCS).sub.6 ].sup.3- and [Mo(2,2'-bipyridine).sub.3 ].sup.3+. U.S. Pat. Nos. 3,489,775 and 4,153,792 describe molybdate salts formed from the reaction of molybdic acid, MoO.sub.3 or molybdenum salts with organic nitrogenous bases. U.S. Pat. No. 4,009,122 teaches a molybdenum catalyst which is the reaction product of an oxygen containing molybdenum compound, an amine and an alkylene glycol. U.S. Pat. No. 4,010,217 relates to coordination complexes of molybdenum or tungsten with nitric oxide.
It is also known that molybdenum dichalcogenides can form intercalation compounds. Intercalation compounds wherein an organic isonitrile is intercalated into the layered structure of Group IVb, Vb, molybdenum and tungsten transition metal dichalocogenides where the chalcogenide is sulfur, selenium or tellurium, are taught in U.S. Pat. No. 4,094,893. The general properties and methods of preparation of intercalation compounds are described in U.S. Pat. Nos. 3,766,064 and 3,688,109. As set forth therein, the intercalate occupies vacant sites between the layers of the metal chalcogenide wherein the chalcogenide is sulfur, selenium or tellurium. The intercalated species include organic and inorganic compounds which are broadly electron donors, electron acceptors, have substantial polarization interactions or are capable of d-orbital bonding. U.S. Pat. No. 4,049,887 relates to an improved cathode containing as active material a layered compound of the formula MA.sub.x B.sub.y where M is Fe, V, Ti, Cr or In, A is O, S, Se or Te, and B is Cl, Br or I.
J. Bernard and M. Camelot, C. R. Acad. Sci., Paris, Ser. C, 263:1068 (1966) report on the reaction of molybdenum trioxide, molybdenyl chloride and molybdenum dioxydichloride with pyridine. The products were identified as addition compounds of the formulae: C.sub.5 H.sub.5 N.MoO.sub.3, (C.sub.5 H.sub.5 N).sub.4.MoO.sub.3.2HCl and (C.sub.5 H.sub.5 N).sub.2.MoO.sub.2 Cl.sub.2. The authors noted that C.sub.5 H.sub.5 N.MoO.sub.3 could only be prepared in sealed ampoules at high temperatures. In a subsequent work, M. Camelot, Revue de Chimie Minerale, 6, 853 (1969), studied addition compounds of pyridine with some oxychlorides or trioxides of chromium, molybdenum and uranium. Based on an infrared spectroscopic investigation, Camelot concluded that C.sub.5 H.sub.5 N.MoO.sub.3 was a molecular coordination compound.
The preparative method described by Camelot or Bernard and Camelot for MoO.sub.3.C.sub.5 H.sub.5 N is similar to a preparative technique for heavy metal chalocogenides intercalated with organic nitrogen compounds described in U.S. Pat. Nos. 3,766,064 or 3,688,109. Molybdenum, however, is not listed as a metal capable of forming a heavy metal layered chalocogenide with, e.g., pyridine. As noted above, Camelot concluded, based on his observations, that MoO.sub.3.C.sub.5 H.sub.5 N was simply another molecular coordination compound similar to CrO.sub.3.C.sub.5 H.sub.5 N and C.sub.5 H.sub.5 N.SO.sub.3.